Peel the sweet potatoes, cut each potato in half cross-wise and then cut each half again length-wise, so you have each potato in 4 pieces. Slice each quarter lengthwise into ½" pieces. Take the long ½" thin pieces and slice them so they are close in shape to long rectangles.
Toss the ½" cubed rectangles in the avocado oil and sprinkle with salt and pepper.
Spread out the fries onto a baking tray or two. Make sure there is a little space between the fries. Place the fries into the oven cook for 25-30 minutes, using a spatula and flipping the fries after 15 minutes.